@FediTips > If you send it in public and include "dm", it reminds you in public.
My experience has been different: a public request for a DM reminder got me a DM reminder.
I could be reading the code wrong but examining the code in the repo (which was last changed 3 months ago), I see the only factor controlling reminder visibility is the DM flag which in turn is determined only by the presence of the string "dm" in the reminder request.